/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
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package org.apache.flink.table.sources.tsextractors

import org.apache.flink.api.common.typeinfo.TypeInformation
import org.apache.flink.table.api.Types
import org.apache.flink.table.sources.FieldComputer

/**
  * Provides the an expression to extract the timestamp for a rowtime attribute.
  */
abstract class TimestampExtractor extends FieldComputer[Long] with Serializable {

  /** Timestamp extractors compute the timestamp as Long. */
  override def getReturnType: TypeInformation[Long] = Types.LONG.asInstanceOf[TypeInformation[Long]]
}
